This invention relates to single use applicators and/or dispensers for applying a polymerizable monomer compound such as cyanoacrylate adhesives, particularly for medical use. The present invention also relates to packaging systems for such applicators.
Numerous swabs, applicators, dispensers and kits for dispensing and applying various materials, including adhesive materials, are known. However, these known arrangements possess various shortcomings that make them undesirable in many applications.
For example, U.S. Pat. No. 5,660,273 to Discko, Jr. discloses a package having wells or depressions for holding a medicament or material and an applicator for applying the medicament or material. The package includes a tray and a cover extending over the entire top surface of the tray. The tray includes an applicator well and a separate medicament well. A mixing area is placed on the cover. The tray further includes medicament wells and an applicator well. However, the ""273 patent does not address providing effective storage and application of a polymerizable monomer compound.
U.S. Pat. No. 5,989,205 to Pond et al. discloses a solution applicator system having a retainer and a plurality of containers for holding a solution, such as fluoride or anesthetic, and an applicator member. Each container encloses the applicator and a solution-retaining receptacle with a puncturable sealing means. The ""205 patent also does not address providing effective storage and application of a polymerizable monomer compound.
Monomer and polymer adhesives are used in both industrial (including household) and medical applications. Included among these adhesives are the 1,1-disubstituted ethylene monomers and polymers, such as the xcex1-cyanoacrylates. Since the discovery of the adhesive properties of such monomers and polymers, they have found wide use due to the speed with which they cure, the strength of the resulting bond formed, and their relative ease of use. These characteristics have made the xcex1-cyanoacrylate adhesives the primary choice for numerous applications such as bonding plastics, rubbers, glass, metals, wood, and, more recently, biological tissues.
It is known that monomeric forms of xcex1-cyanoacrylates are extremely reactive, polymerizing rapidly in the presence of even minute amounts of an initiator, including moisture present in the air or on moist surfaces such as animal (including human) tissue. Monomers of xcex1-cyanoacrylates are anionically polymerizable or free radical polymerizable, or polymerizable by zwitterions or ion pairs to form polymers. Once polymerization has been initiated, the cure rate can be very rapid.
Medical applications of 1,1-disubstituted ethylene adhesive compositions include use as an alternate or an adjunct to surgical sutures and staples in wound closure as well as for covering and protecting tissue wounds such as lacerations, abrasions, burns, stomatitis, sores, and other open surface wounds. When such an adhesive is applied, it is usually applied in its monomeric form, and the resultant polymerization gives rise to the desired adhesive bond.
However, due to the need to apply the adhesive in its monomeric form, and due to the rapid polymerization rate of the monomers, it has been very difficult to design effective and commercially viable packaging systems. Such packaging systems must counterbalance the competing requirements that the monomer not prematurely polymerize, that the monomer be easily applied, that the monomer polymerize at a desired rate upon application, and that the sanitary and/or sterile properties of the monomer and applicatorxe2x80x94whether real or perceivedxe2x80x94be maintained. This latter requirement, that the actual or perceived sanitary and sterile condition of the monomer and applicator be maintained, is particularly important in medical applications, where the user and/or the patient desires a clean product so as not to introduce further bacteria or foreign matter into a wound site.
In order to meet the above requirements, various packaging systems for monomeric adhesives have been proposed. These systems include large bottles with a single applicator, such as a large single- or multi-use brush; small applicators such as small ampoules containing monomer, for example within an internal frangible vial, that can be expelled through an integral applicator; and the like. However, a problem with many of these applicator systems is that the product contains more adhesive material than is necessary for a particular use. Because of the rapid polymerization rate of the monomers, any unused adhesive must often be discarded, because the remaining monomer undergoes polymerization, often within the applicator, to render the applicator unusable.
A further problem in addressing the above requirements of adhesive applicators and packaging is the need to provide a stable monomer product. Particularly in small quantities, such as single-dose sizes, cyanoacrylate monomers are prone to premature polymerization, which would render the product useless. Thus, industrial production of monomeric adhesive compositions has had to balance rapid cure rates and high bond strengths with shelf-life. The shelf-life of these adhesives is primarily related to stability (i.e., constancy of compositional nature), uncured physical properties, rate of cure of the adhesive, as well as final cured properties of the composition. For example, the shelf-life of a monomeric xcex1-cyanoacrylate composition may be measured as a function of the amount of time the composition can be stored before unacceptable levels of polymerization, such as measured by viscosity increase, occur. Unacceptable levels are indicated by a level of polymerization product that reduces the usefulness of the composition in the application for which it is produced.
One proposed solution to this reduced shelf-life problem is to incorporate one or more stabilizers into the adhesive composition. For example, as disclosed in U.S. Pat. Nos. 3,559,652 to Banitt et al. and 5,582,834 to Leung et al., suitable stabilizers for medically useful xcex1-cyanoacrylate compositions include Lewis acids such as sulfur dioxide, nitric oxide, and boron trifluoride, as well as free-radical stabilizers including hydroquinone, monomethyl ether hydroquinone, nitrohydroquinone, catechol, and monoethyl ether hydroquinone. The combination of the two anionic stabilizers sulfur dioxide and sulfonic acid is also known and is disclosed in, for example, British Patent Application GB 2 107 328 A.
However, while the proposed solution of adding stabilizers provides compositions that are more stable, a different problem arises. That new problem is that as the concentration of the added stabilizers increases in the composition, the cure rate of the composition tends to decrease. Thus, further components must be provided, such as in a separate composition, to be mixed with the adhesive composition (either directly or at the application site) to increase the polymerization rate of the monomer. Such additional materials, such as polymerization initiators or rate modifiers, increase the cost of the final composition, and may increase the complexity of use of the composition.
Known devices fail to provide a disposable package assembly that is optimized for convenient dispensing and application of adhesive materials on a variety of surfaces and structures. The known applicators are generally either optimized for delivery of other compositions or are inconvenient for use in conjunction with adhesives. Furthermore, such conventional devices and packaging generally do not address the competing needs of ease of use and adhesive stability prior to application.
The present invention addresses the above needs by providing applicators and dispensers that permit economical and efficient use of adhesive compositions. In embodiments of the present invention, applicator assemblies and dispensers are provided whereby single-use applicators/dispensers are provided with single-use amounts of adhesive material, thereby avoiding waste of excess adhesive material. The applicators and dispensers can be provided in multiple different sizes, to account for situations where more or less adhesive material may be required.
In embodiments, an applicator and an adhesive composition are packaged in a material that provides acceptable stability and shelf-life to the adhesive composition without the need to add separate stabilizer materials to the polymerizable monomer. Thus, in these embodiments, because the shelf-life is provided by the packaging material itself, the cure rate of the adhesive composition is not adversely affected, as in the case where one or more stabilizers are added. Accordingly, the need to apply separate polymerization initiators or rate modifiers can be reduced or even eliminated.
In other embodiments, the applicator assemblies include a polymerization initiator or accelerator for the adhesive material. The polymerization initiator or accelerator may be disposed in or on a tip or other part of the applicator. The tip or other portion of the applicator may be at least one of porous, absorbent and adsorbent in nature and the polymerization initiator or accelerator may be absorbed or adsorbed into the portion of the applicator. The applicator assemblies may also include a frangible barrier separating first and second compartments, for example, to keep the polymerization initiator or accelerator separated from the adhesive material prior to use.
In further embodiments, the applicator assemblies include first and second compartments that are open to each other with the polymerizable monomeric adhesive material contained in the first compartment and the applicator at least partially disposed in the second compartment. The applicator assemblies may further comprise a plunger that defines the second compartment and that is movable into the first compartment to displace the adhesive material into the second compartment. Thus, small volumes of adhesive material may be easily dispensed.
In particular, the present invention is directed to an applicator assembly for dispensing and applying a polymerizable monomeric adhesive material, comprising: a base portion having at least one sealed compartment; a polymerizable monomeric adhesive material contained in the at least one compartment; and an applicator at least partially disposed in the at least one compartment such that a tip of the applicator is proximate the polymerizable monomeric adhesive material; wherein removal of at least one of the applicator and the adhesive material requires the applicator assembly to be destructively unsealed.
In embodiments, the at least one sealed compartment may comprise a first sealed compartment and a second sealed compartment. The first and second compartments may be separated, with the polymerizable monomeric adhesive material contained in the first compartment and the applicator at least partially disposed in the second compartment. In embodiments, a frangible barrier separates the first and second compartments. In other embodiments, a substantially nonfrangible barrier separates the first and second compartments. In still other embodiments, the first and second compartments are open to each other.
In embodiments, a dispenser for a polymerizable monomeric adhesive material is made of a material that provides acceptable stability and shelf-life to the adhesive composition without the need to add separate stabilizer materials to the polymerizable monomer. As noted above, because the shelf-life is provided by the material of the dispenser, the cure rate of the adhesive composition is not adversely affected. Thus, the need to apply separate polymerization initiators or rate modifiers can be reduced or even eliminated.
In other embodiments, the dispensers include a polymerization initiator or accelerator for the adhesive material. The polymerization initiator or accelerator may be disposed in a separate reservoir of the dispenser that is preferably sealed from the adhesive material and/or the atmosphere. The seal for the initiator or accelerator and/or the adhesive material may comprise a frangible barrier, a cap, a deformable portion, a friction fit between parts or the like.
In particular, the present invention is directed to a dispenser for a polymerizable monomeric adhesive material, the dispenser including a first dispenser element defining a first reservoir, the first dispenser element having an open end and a closed end; a second dispenser element defining a chamber, the second dispenser element having an open end, a closed end and at least one aperture disposed between the open end and the closed end, the at least one aperture opening into the chamber; and a polymerizable monomeric adhesive material contained in the first reservoir, wherein at least the closed end of the second dispenser element is received in a first position by the first dispenser element to seal the adhesive material in the first reservoir.
In embodiments, a first circumferential ridge portion is situated between the closed end of the first dispenser element and the at least one aperture of the second dispenser element when the closed end of the second dispenser element is in the first position. The first circumferential ridge portion may be disposed on an inner surface of the first dispenser element or on an outer surface of the second dispenser element. The dispenser may also include a second circumferential ridge portion situated between the open end of the first dispenser element and the at least one aperture of the second dispenser element when the closed end of the second dispenser element is in the first portion. In embodiments, the first and second circumferential ridge portions form a continuous circumferential ridge.
In embodiments, the chamber and the at least one aperture comprise a second reservoir. A second material, such as a polymerization initiator or accelerator for the adhesive material, may be contained in the second reservoir. In other embodiments, the adhesive material may be contained in the second reservoir with the second material contained in the first reservoir.
In other embodiments, the present invention is directed to a dispenser for a polymerizable monomeric adhesive material, the dispenser comprising: a dispenser element defining a first reservoir, the dispenser element having an open end and a closed end; a circumferential ridge portion disposed on an inner surface of the dispenser element between the open end and the closed end; a stopper element sealingly fitted against the circumferential ridge portion to seal the first reservoir and define a chamber between the stopper element and the open end; and a polymerizable monomeric adhesive material contained in the first reservoir.
In embodiments, the circumferential ridge portion is deformable to release the stopper element. In other embodiments, the chamber comprises a second reservoir that may contain a second material. Alternatively, the second material may be contained in the first reservoir with the polymerizable monomeric adhesive material being contained in the second reservoir.
The present invention is also directed to kits, including one or preferably more of the applicator assemblies or dispensers. The applicator assemblies or dispensers can be provided with different amounts of adhesive, and/or different size applicators, and/or different amounts of polymerization initiator or accelerator.